Title: Improved control scheme of stand-alone DFIG-based wind energy conversion system with battery energy storage system

Authors: Dan-Yun Li; Qun-Tai Shen; Zhen-Tao Liu; Hui Wang

Addresses: School of Automation, China University of Geosciences, Wuhan, Hubei 430074, China; School of Information Science and Engineering, Central South University, Changsha, Hunan 410083, China ' School of Information Science and Engineering, Central South University, Changsha, Hunan 410083, China ' School of Automation, China University of Geosciences, Wuhan, Hubei 430074, China ' School of Information Science and Engineering, Central South University, Changsha, Hunan 410083, China

Abstract: An improved control scheme for stand-alone DFIG-based wind energy conversion system is proposed. The intermediate DC-link of back-to-back PWM converter is supported with a battery energy storage system to smooth the fluctuation of power caused by the variation of wind speed and loads. A three-phase four-leg converter is employed as the Stator-Side Converter (SSC) to provide a path for the zero-sequence current. Based on the modified topology, the stator voltage of DFIG is directly controlled by the SSC. And the rotor speed of DFIG is regulated by the rotor-side converter for maximum power point tracking. Modified repetitive controllers incorporated with the state-feedback controllers are adopted for the SSC to ensure the desirable stator voltage even under the unbalanced loads or non-linear loads conditions. The proposal avoids the complicated operation of the harmonic extraction, and the positive- and negative-sequence current decomposition, which is verified by the simulation results.

Keywords: three-phase four-leg converters; PWM converters; modified repetitive control; nonlinear loads; unbalanced loads; standalone DFIG; doubly-fed induction generators; wind energy conversion; wind power; battery energy storage systems; wind speed; stator-side converters; SSC; rotor speed; maximum power point tracking; MPPT; simulation.

DOI: 10.1504/IJCAT.2016.079874

International Journal of Computer Applications in Technology, 2016 Vol.54 No.3, pp.211 - 219

Available online: 09 Oct 2016 *

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